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Author Topic: How could we make an atmosphere in Mars?  (Read 7377 times)

Offline alancalverd

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Re: How could we make an atmosphere in Mars?
« Reply #25 on: 07/07/2015 01:01:16 »
Quote from: alancalverd
Solar wind is not the problem. Lack of gravity is. If your atmosphere is at a breathable temperature it will diffuse away into space if not held by sufficient gravitation (or a plastic bubble).   
And what would that be for Mars? Consider the fact that Earth has a surface pressure of about 1 bar whereas Venus has a surface pressure of about 92 bars. The mass of Venus is about 80% the mass of Earth. The atmosphere or Venus didn't exactly diffuse away into space.

A good point. The difference is the chemical composition of the atmosphere and certainly not the solar wind, which is a lot stronger on Venus. Except that the chemical composition of both atmospheres is effectively identical - about 95% carbon dioxide.

So it must be that Mars is so much colder. But Neptune is even colder and has a surface pressure of over 1000 bar.... 

So the answer is...I don't know!

Anyone out there care to enlighten me?
 

Offline lungo

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Re: How could we make an atmosphere in Mars?
« Reply #26 on: 07/07/2015 02:24:04 »
Going a little off topic.
Have you considered items that might be in short supply and change the way Martians live? We use a lot of plastic, but Mars without access to oil (except by expensive import) might need to find alternatives eg plant fibres, casein plastic from milk, etc.
I don't know the geological make up of Mars but some minerals will be plentiful and others very rare, this will influence what can be made locally.

Good point mate. It is a major plot point that, because oil and workable ore deposits of basic minerals on Earth were depleted a long time ago (oil replaced by better bioplastics, carbon composites) export of refined minerals is a major component of the Martian economy. Because Mars isn't entirely self sufficient and many components and supplies necessary for heavy industry are still imported from Earth this co-dependency makes the push for Martian self-determination all the more complicated, both for people on Mars and Earth.

There's suggestive evidence of large deposits of iron, aluminum, titanium and magnesium in Mars found by Spirit and Opportunity, the rovers also found trace amounts of chromium, cobalt, nickel and zinc but maybe such deposits aren't rich enough to be exploited, again putting Mars further away from sef-sufficiency. Also, haven't found any reference to existing phosphates, essential for agriculture in what could be a relatively barren soil. Maybe a major Martian import is guano?

I'm working on the basis that regular supplies from Earth arrive in Mars faster and cheaper than they would in the present day: supplies from Earth are put in orbit via a space elevator, loaded onto a ship that takes the cargo to Mars (fusion propulsion is the working assumption) On Mars the lower gravity allows heavy shipments of mined minerals, refined on site, to be loaded onto unmanned capsules and put in orbit by a giant rail gun, once there they are directed towards Earth by their own thrusters. Upon arrival on Earth's orbit the capsule is taxied, docked onto the space elevator platform and unloaded. The same capsule is loaded again and used to carry supplies from Earth to Mars, then launched from the ship and towards the Martian surface, using a parachute and the aforementioned thrusters to ease the touchdown. Although the capsule is reusable the guides that make contact with the rails on the rail gun when launching from Mars need to be changed every time.

Things to wonder about: Oil on Earth and Mars replaced by better bioplastics than we have today?  Would it be easier to transport entire heavy industrial facilities a few pieces at a time (thinking furnaces, foundries, forges) or build them from scratch? Regarding Mars ore deposits, what am I missing? What is and isn't there that would be essential?
Also (and I'm really loving writing about this bit) any better ideas on how the import/export operation to and from Mars would work?
Waiting for some suggestions!
 

Offline evan_au

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Re: How could we make an atmosphere in Mars?
« Reply #27 on: 07/07/2015 10:40:36 »
Quote from: evan_au
...we know that there is a layer of frozen water under the red dusty surface of Mars.
I remember seeing the images taken by a Mars lander, showing a white patch blasted out by the landing rockets, and the white scrapes made by the sample collector - this is what led me to think that there definitely was ice on Mars.

But when I looked up which Mars lander (Phoenix), and the conclusions from its experiments, it appears that its not 100% certain that it was water ice, with some alternative hypotheses floating around (eg perhaps it was salty water or dry ice=CO2).

Apparently, some of the instruments did not work perfectly, and samples got stuck in the in-tray, making the analysis less than definitive.
 

Offline David Cooper

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Re: How could we make an atmosphere in Mars?
« Reply #28 on: 07/07/2015 18:40:11 »
How certain are you, Alan, that the solar wind isn't a key factor in depleting the atmosphere on Mars? I've heard it blamed for it on science programmes which point out that the magnetic field on Mars is extremely weak and incapable of deflecting the solar wind away in the way that the Earth's does.

On the issue of whether there's water on Mars or not, there's plenty of evidence that something liquid has been running about over the surface in very recent times and will still be around in large quantities under the surface, and water is the most likely candidate. It certainly isn't CO2 or methane.
 

Offline chiralSPO

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Re: How could we make an atmosphere in Mars?
« Reply #29 on: 07/07/2015 20:51:14 »
Venus doesn't have a magnetic field either (though I suppose its CO2 and SO2 atmosphere is less susceptible to depletion by solar wind...)

Mars has a substantially weaker gravitational field than Venus, Earth or Neptune. On the other hand, it is also about 5 times as massive as Titan, which has plenty of atmosphere!

It must not be a very simple explanation, but my guess is that a combination of the low mass, weak magnetic field, relative proximity to the sun, temperature, and initial composition of the atmosphere has lead to the present state of the Martian atmosphere.

It would appear that much of its CO2 is solidified, and most of its nitrogen is lost...
 

Offline fmartinie

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Re: How could we make an atmosphere in Mars?
« Reply #30 on: 08/07/2015 01:42:01 »
its possible to create a sort of massive dome and from the inside of that dome you could create an artificial environment that is suitable for life and maybe an atmosphere ? depends on how you want your story to go but this is just another idea.
 

Offline lungo

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Re: How could we make an atmosphere in Mars?
« Reply #31 on: 08/07/2015 07:33:09 »
Hi everyone,

Found this really interesting paper on technological requirements for the terraforming of Mars,
newbielink:http://www.users.globalnet.co.uk/~mfogg/zubrin.htm [nonactive]
As laid out here the process would start by generating a greenhouse effect on Mars, either through crashing ammonia rich comets on the surface of by artificially producing large quantities of CFC's directly from a facility on the Martian surface, although this last effort would most likely involve at least a rotating crew of people operating it.
Second stage would start with the deployment of large mirrors of mylar or a mylar-like material (starting at a "modest" 125 km radius) to reflect sunlight onto one or both poles, likely candidates for the presence of frozen CO2 and/or water. Solar wind would prevent the mirror from orbiting and keep it in a relatively stationary position, allowing the concentration of reflected sunlight in a specific area of the planet causing a steady rise in local temperature. While contributing to raise pressure it would create an environment appropriate for moving onto stage 3, in which suitable vegetation and/or micro-organisms (perhaps genetically engineered) could thrive and self-propagate.
Most convincing study I've found so far, please let me know how you like it. An interesting observation is the fact that a mirror that big couldn't possible be launched from Earth ready to deploy, but rather would need to be assembled in zero gravity.

On a different note:

Venus doesn't have a magnetic field either (though I suppose its CO2 and SO2 atmosphere is less susceptible to depletion by solar wind...)


Sorry if the question is a bit basic, but why would certain gasses be more susceptible to solar wind than others?
The question of why bodies of a similar mass have held on to an atmosphere while Mars hasn't is definitely one the most interesting. On the matter of the absence of a strong magnetic field (as far as my understanding goes due to the lack of a molten core) why is the core solid? is the pressure itself what keeps the Earth's core molten? if so, is the lower mass of Mars to blame? and is the chemical composition of the core itself a crucial factor?
« Last Edit: 08/07/2015 07:47:25 by lungo »
 

Offline lungo

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Re: How could we make an atmosphere in Mars?
« Reply #32 on: 08/07/2015 07:44:03 »
its possible to create a sort of massive dome and from the inside of that dome you could create an artificial environment that is suitable for life and maybe an atmosphere ? depends on how you want your story to go but this is just another idea.

Hi there. This was an initial consideration actually, but the presence of a breathable atmosphere gives me a much more interesting scenario to work with given the direction the story takes. Perhaps the creation of such a dome does prove necessary during stage 1 as a base to host the people working on the CFC factory mentioned above.
 

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Re: How could we make an atmosphere in Mars?
« Reply #32 on: 08/07/2015 07:44:03 »

 

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